In the cell biology field, there has been recently used a cell sorter which separates only specific cells from a cell population in a sample liquid. This cell sorter can distinguish cells by irradiating a sample liquid dropwise injected (liquid floating cells or suspension of cells) with laser light and measuring scattered light, fluorescent light or the like. Further, specific cells can be separated into predetermined tubes by applying electric field or magnetic field.
However, this type of device has problems such as damage on the cells in the separation process, low accuracy of separation or low throughput of separation. Further, there is another problem that it is not observable whether the separation of each of the cells is appropriately performed.